The present invention relates generally to a method and apparatus for embossing and crimping a multi-layer sheet material web assembly, and in particular, to a method and apparatus for embossing and crimping a multi-layer sheet material web by forming a pattern of embossments in the layers of the sheet material web assembly, a portion of which further comprise crimps to bind the layers together. The invention also relates to a multi-layer sheet material web assembly having a pattern of embossments and crimps.
It is well known in the field of paper making, and particularly in the field of manufacturing tissue products such as facial tissues, bath tissues and paper towels, to form a sheet material web assembly having a plurality of layers, or plies. Often, the individual layers of sheet material web, or the assembly as a whole, are provided with embossments, or raised portions, which can improve important product qualities of the assembly, such as the softness, water absorbency and bulk thereof. Often, the embossments are arranged in an aesthetically pleasing pattern to improve the overall appearance of the assembly.
In such multi-layer configurations, the individual layers of sheet material web are usually joined together to form the web assembly. Typically, the layers are joined with adhesives or crimping, or some combination thereof. Often, when crimping is used to bind the layers, the crimps are formed independent of the pattern of embossments, for example, in the form of lines running along the machine direction of the web assembly. Such crimp lines can interfere with the embossing pattern so as to detract from the pleasing appearance thereof. Alternatively, adhesives can be difficult to apply, and the application thereof can increase the cost of the web assembly.